Blocking the Blueprint: Technological Barriers Against 3D-Printed Firearms – GNET

Introduction

Over the last decade, consumer 3D printing technology has advanced rapidly, driven by the expiration of numerous patents and the growth of a large, global online community of designers, tinkerers, and hobbyists. These developments have significantly influenced the 3D-printed firearm (3DPF) movement. What began as basic single-shot handguns has evolved into extremely sophisticated and reliable firearms. Alongside firearms, 3D-printed accessories such as magazines, suppressors, and optics have also advanced significantly. One particularly concerning trend is the rise of 3D-printed conversion devices (often known as auto-sears or switches)—small components that can convert semi-automatic firearms into fully automatic weapons.

While a significant portion of the 3D-printed firearm community operates lawfully in the United States, where the First and Second Amendments protect many such activities, these developments have not gone unnoticed by insurgents, terrorists, and extremists. Additionally, criminal networks worldwide have turned to 3D-printed firearms as both a lucrative source of income and a means of arming themselves.

Faced with this phenomenon, lawmakers worldwide have sought to introduce legislation to curb the manufacturing of 3D-printed firearms. In Canada, as of 1 September 2024, individuals must possess a valid firearms license to acquire or import essential firearm parts, including barrels and handgun slides. In New South Wales, Australia and Singapore, it is illegal to possess 3D-printed firearms and related files. In the United States, President Biden signed an executive order to establish an “Emerging Firearms Threats Task Force” to address the growing issue of 3D-printed firearms and machine gun conversion devices.

While these initiatives show promise, they are often seen as incomplete measures, focusing solely on individual behaviour rather than addressing the broader role of 3D printing technology in firearm manufacturing. Although other methods of fabricating privately manufactured firearms exist, such as metal folding and bending, casting, and milling, 3D printing has significantly lowered the skill barrier. Therefore, means to address the illicit production of firearms must also centre on the technology at hand. This Insight proposes a multi-faceted approach to combating the proliferation of 3D-printed firearms by exploring potential technological countermeasures. To tackle the issue more effectively, it suggests incorporating elements of Design Against Crime (DAC) directly into the software, hardware, and materials used in 3D printing.

Design Against Crime is both an academic and practical initiative that originated in the UK. It aims to incorporate crime prevention into the design of products, environments, services, and systems. The approach reduces opportunities for crime by embedding crime-prevention features directly into the design process. Developed as collaborative efforts between researchers, designers, and industry, DAC provides a framework for integrating safety measures across various sectors.

Elements of Design Against Crime that could help raise the barriers to firearm production using 3D printers already exist in current technologies. To conceptualize various Design Against Crime approaches to 3D printing, it is helpful to break down the process of turning Computer-aided design (CAD) files into 3D objects into three distinct levels of interdiction: the slicer software (software level), the 3D printer itself (firmware level), and the filament (material level).

Software Level Interdiction

Slicer software is a critical tool in 3D printing that converts a 3D model (usually in CAD format) into a set of instructions that the 3D printer can follow. This software “slices” the model into horizontal layers and generates G-code, a language that guides the printer’s movements. Different types of slicer software exist, ranging from open-source options like Cura and PrusaSlicer to proprietary versions like Simplify3D and FlashPrint.

Inspiration for software-level interdiction could be drawn from the Counterfeit Deterrence System (CDS), a technology embedded in digital imaging software, such as Photoshop, that prevents the replication of banknotes. The CDS works by recognising specific patterns and then preventing users from opening, editing, or printing the image.

Figure 1: Adobe Photoshop detects an attempt to edit banknote images and activates its built-in Counterfeit Deterrence System (CDS), preventing users from printing or modifying currency.

Similarly, a mechanism could be implemented within commercial slicer software to recognise known 3D-printed firearm models or parts and stop their processing. Commercial slicer software companies would need to be fully on board, implementing these recognition algorithms as part of their product’s core features. While this may work for large, commercially produced slicers, it becomes far more challenging with open-source software. Without specific legislation mandating the inclusion of these security features, integrating similar interdiction measures into open-source slicer software could prove difficult, if not impossible.

A potential interim solution might be to enable slicers to block the processing of 3DPF parts and accessories voluntarily—either as an add-on software or an admin-level option within the software itself. This approach would be particularly useful for institutions like schools, libraries, universities, and creative building spaces, allowing them to safeguard their equipment against misuse and unauthorized activities.

Firmware Level Interdiction

In the late twentieth century, advances in computer and photocopy technology made it possible for individuals without specialized training to replicate currency. In response, document output devices such as traditional photocopiers and 2D printers began incorporating various anti-counterfeiting features at the firmware level. Firmware refers to the built-in software embedded within a device’s hardware that controls its fundamental operations. Unlike regular software, which users can modify or replace, firmware is deeply integrated into the device, making these security features difficult to bypass or tamper with. Firmware measures to counter the misuse of emerging technology have been implemented in the UAV sphere, with mixed results. Several producers of commercial drones have integrated built-in software restrictions, such as geofencing for GPS-enabled drones. Geofencing uses GPS data to create virtual boundaries that prevent drones from entering restricted or sensitive areas, like airports or government buildings.

One such measure that could inspire efforts to counter the proliferation of 3DPF, similar to the CDS, is the use of OMRON Rings—a pattern of small yellow, green, or orange circles arranged in a specific configuration and subtly embedded into the design of banknotes. When attempting to photocopy or scan a banknote containing OMRON Rings, most modern photocopiers, scanners, and printers detect this pattern at the firmware level, automatically stopping or distorting the copying process to prevent unauthorized reproduction. While incorporating similar elements within 3D printing files to facilitate detection is unlikely to be effective, firmware could be designed to recognise and halt the production of specific patterns or shapes associated with known privately manufactured firearm designs.

One significant challenge in detecting and recognising 3D-printed firearms is the sheer volume and variety of designs. A recent study uncovered more than 2,100 different 3D-printed firearm plans between 2021 and 2023 alone. In addition, the constant influx of new files and plans makes it difficult for interdiction measures to keep pace. Many of these designs are “remixes” or modifications of existing models, incorporating slight changes to their structure or components. These subtle variations can easily evade detection algorithms that rely solely on a database inventory of known firearm patterns.

A potential way to overcome this difficulty is for software or firmware-level interdiction to use machine learning. Instead of depending on a static database of designs, machine learning algorithms could be trained to identify potential firearm parts based on common features and patterns. This dynamic approach would allow interdiction measures to adapt to new or modified designs in real-time, enhancing their ability to recognise firearms regardless of subtle structural changes or remixes.

In addition to offering a promising approach to limiting the production of 3D-printed firearms, firmware-level interdiction can also tackle the challenging task of tracing the origins of a 3DPF. This task is made more difficult by the lack of traditional markings and serial numbers typically required on commercially manufactured firearms.

In recent years, several new strategies have been developed to trace a particular firearm back to a specific 3D printer. These methods involve matching unique patterns created by the printer’s hot-end nozzle or fine marks left on the printer bed to those found on a 3DPF, helping to link the firearm to its source. Additionally, existing Design Against Crime features incorporated into traditional 2D printers could aid in identifying a 3DPF’s origin.

Although their existence only became public in 2004, many traditional 2D printers had already been embedding Machine Identification Codes for years. These codes are composed of tiny, nearly invisible yellow dots printed on every page. They encode crucial information, such as the printer’s serial number, model, and the date and time of printing, allowing law enforcement agencies to trace the source of printed documents as a measure against counterfeiting and other illegal activities. This technology is believed to have been instrumental in identifying Reality Winner, a former intelligence contractor who leaked classified information to the media, leading to her arrest and conviction.

A similar approach could be employed for 3D printers by incorporating a tracking system that embeds unique identifiers, such as microscopic markings or codes, into the surface of every 3D-printed object. These markings could contain information about the printer’s serial number, model, and the date and time of printing. Integrated directly into the printer’s firmware, this system would automatically and discreetly apply these identifiers during the printing process, making it nearly impossible for users to alter or remove them. Such a method would provide law enforcement with a powerful tool to trace a 3D-printed firearm back to the specific printer used, facilitating investigations and potentially deterring illegal manufacturing by ensuring traceability.

Material Level Interdiction

Recent research has shown promise in using chemical analysis to link polymer traces found after the discharge of a 3DPF to specific types, brands, and colours of commercial filaments. However, efforts to trace a 3DPF to its point of origin could be further enhanced if filament manufacturers adopt Design Against Crime practices, similar to the use of identification (post-detonation) chemical taggants in industrial explosives.

Chemical taggants are unique markers or additives mixed into a material to enable identification and traceability. In the context of industrial explosives, taggants have been introduced to facilitate the identification of the manufacturer and batch number following a detonation. For instance, since the 1980s, all explosives manufactured in Switzerland are required to contain taggants.

In the 3D printing sphere, taggants have been discussed as a way to counter counterfeits by embedding unique chemical markers or identifiers directly into the printing filament during the manufacturing process. This means that the printed object can later be analysed to identify the filament’s specific batch, manufacturer, and other details. In other words, these taggants act like a “fingerprint” for each filament batch, allowing the material used in a printed object to be traced back to its source. This helps authenticate the origin of a printed item, making it easier to distinguish genuine products from counterfeits.

The inclusion of taggants in commercial 3D printing filament could also assist in criminal investigations. If a 3D-printed firearm is recovered, the embedded taggants in the polymer could identify the specific filament used, thereby providing a lead to the printer’s owner or the source of the material. Additionally, it would allow investigators to chemically match firearms made using the same filament or filament purchased in batches.

Constraints

None of the aforementioned technological solutions represent a panacea. Each faces significant constraints that limit its effectiveness and implementation.

Incorporating these interdiction features would require manufacturers to comply voluntarily or through regulation. However, there are several reasons why the industry might resist voluntary compliance. First, such measures could increase production costs and complexity, which many manufacturers, especially smaller companies, may be unwilling to bear, particularly if they fear it could make their products less competitive in the market. Additionally, some manufacturers might view these features as an infringement on consumer rights or privacy, especially within communities that advocate for the open-source nature of 3D printing and resist any form of control over their equipment. In fact, some manufacturers have formed strong ties with the 3DPF community; for example, Polymaker, a filament producer, has entered into sponsorship arrangements with influencers within the 3DPF community and are, therefore, unlikely to voluntarily adopt such measures.

From a regulatory standpoint, the implementation of such features poses several challenges. Creating and enforcing regulations would require significant global coordination, as 3D printing technology and filament production are not confined to any single country. Different nations have varying legal frameworks for firearms and privacy rights, making it nearly impossible to create standardized regulations that all manufacturers must follow. This not only complicates enforcement but also risks creating a fragmented market where some manufacturers comply with regulations while others do not, potentially undermining the effectiveness of global efforts.

The 3DPF community has repeatedly demonstrated its ability to quickly adapt to regulatory measures and crackdowns, implementing new procedures and processes both in the design of firearms and in manufacturing methods.

Despite these constraints, implementing these technological solutions would nonetheless significantly raise the barriers for the production of privately manufactured firearms. The proliferation of 3D printing has drastically lowered these barriers, allowing more widespread access to firearm manufacturing. By incorporating these security features, whether at the software, firmware, or material level, it is possible to partially restore the difficulty of creating PMFs, thereby helping to mitigate the risks associated with their unregulated production—ideally without stifling lawful innovation.

Yannick Veilleux-Lepage, PhD, is an Assistant Professor in the Department of Political Science and Economics at the Royal Military College of Canada. His research focuses on the intersection of technology, terrorism, and the evolution of terrorist tactics. He is also the Scientific Director of Pier Point Consulting, a firm specializing in providing analysis and threat assessment related to misuse of emerging technology.

This Insight builds on themes addressed in his remarks on 25 September 2024 at the International Institute for Justice and the Rule of Law (IIJ) UNGA Side Event on Emerging Technologies and Counterterrorism: Criminal Justice Policy Implications in New York City.